Electric signaling system.



No. 882,276. PATENTED MAR. 17, 1908. J. D. TAYLOR.

ELECTRIC SIGNALING SYSTEM.

APPLICATION FILED JAN. so, 1908.

MW (SM WITNESSES UNITED- STATES PATENT OFFICE.

JOHN D. TAYLOR, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYL- vANIA.

'To all whom it may concern:

Be it known that 1, JOHN D. TAYLOR, of

' Edgewood Park, Allegheny county, Pennsylence being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a viewshowing diagrammatically one embodiment of my invention; Fig. 2

is a similar diagram, showing the presence of strain in one of the blocks; and Figs. 3 and 4 are detail views showing one way of providing for increased impedance in portions of the track rails.

' My invention has relation to block-signah ing systems, more particularly designed for use on railroads employing electric propulsion and to that class ofthe said systems in which the track rails instead of being separated into insulated blocks or sections, are electrically continuous for all currents. The

. terms blocks and sections as used herein, are therefore not intended to designate actuallv separated blocks or sections of the track, ut are used for convenience to designate the ortions of the tracks which are between ad a'cent signals.

.In continuous rail systems which have heretofore been proposed, there has been considerable indeterminateness in the block limits, due to the fact that the exact points at which the signal controllin lelays would be shunted or short-circuite by a train,

could not be directly located or fixed in all cases by reason of changes in track conditions:

An important object of my invention is to rovide means in a'system of this character or rendering the block limits more determinate and the broadly novel feature of m invention consists in providing the tracr railsadjacent to the points where the signalcontrollin relays are connected thereto with portions 0 increased im science which operate to more closely 00 e and localize the points at which the respective relays will be operated by trains,

The precise nature of my invention will be best understood b reference-to the accompanying drawing iagrams, m which I have' Shown one embodiment thereof, it being pre- Specification of Letters Patent.

application filed Janusry 30, 1908. Serial No. $13,891.

ELECTRIC srenanme SYSTEM.

Patented March 1'7, 1908.

B is an alternating current generator for supplying the signaling circuit. This generator should be adapted to give a current of considerably higher frequency than the generator which supplies the propulsion current Where that generator is an alternator. The current from the generator B is led to the various signaling instruments by means of the line wires or conductors j, k.

c and c designate transformers whose primaries p, are connected across the condoctors 7', I and whose secondaries s, s are connected across the track rails 'r, r, at as nearly as may be the middle point of the blocks which they respectively supply. The

rails 1', r are electrically continuous for all currents. Those portions of these rails at and adjacent to each end of each block are provided with means for increasing their impedance, as indicated at g, g. This may be conveniently efiected by adding iron to each side of the rails between their heads and flanges. This iron is referably laminated, as shown in Figs. 3 and 4, for the purpose of preventing the current which should flow in the rail from dividing and the part going through the added iron. This added iron acts to increase the impedance of the rails by forming a complete magneticcircuit around the current carried by the rails, and in effect multiplies their impedance many times. These reinforced sections of the rails are 10- cated, as stated, at the ends of the blocks opposite the signals S, S. The relays which control these signals are connected across the rails at the extreme ends of the reinforced sections. These relays are designated by the letters R, R, R, R, etc. They are of a type having two elements, one energized from the track circuit, and the other from the line wires y', 7c. in the arrangement mised, however, that various changes may be nected 'tothe rails o positely, that is to say,

the.positive termina offlthe transformer C is connected to the same trackrail as the negative terminal of the transformer .C'. The

relays between each two transformers are connected to the line and across the track rails in such sense that the current from anysection g.

transformer except the one intended to operate the relay, will be in the wrong direction to close its contacts, and will, therefore, tend to open its contacts. The arrows in the diagrams indicate the direction of the flow of.

current at any instant, and the figures preceded by the plus or minus signs indicate the otentials'at the'various points corresponding to the currents indicated by the arrows. These figures are, however, 'merely hypothetical, being used for the purpose of illustration only, and may have any values within reasonable limits. The secondarys of the transformer C will, at a given instant, produce a potential plus.5,-in the illustration given, at its connection with the rail r, tending to cause a current to flow in the direction indicated by the arrow; and it may be assumed that the impedance'of the rail 0" is such that the fall of potential will be four volts between the point plus 5 and the point plus 1 at the extremity of the reinforced rail From the point plus 1 to the other extremity of the reinforced section g the potential falls two more volts to minus 1; thence through the rail 1* there is a further dro of four volts to the terminal of the secon ary s of the transformer C In the other rail 1*, the fall of potential is of equal amount, but in the reverse direction. This supposed case gives a difference of two volts of potential, tending to force current through each of the armatures a, a of the-relays R,

R. Thevfields f, f of the same rela s are energized from the line conductors j, and in such direction that the currents therein coactingwith the currents in the armatures derived from the track rails will cause the armaturesto move and close the contacts e, e

The end of each of the blocks is similarly equipped, and each signal is controlled by two relays, one at each end of the block, and supplied by current from a transformer between them andthetwo rela s of each blockhaving the contacts contro ed thereby in series in the local or signal controlling circuits,

When a train stands on any part of the track section between a relay and the trans-' former supplying that relay, current is out off from the relay and the signal circuit is o ened, causing the signal to go to danger.

he shunting of each relay w ll, of course, occur a short time before the train reaches 'at the potential zero. 7

points may, therefore, be joined by asolid conductor if desired without affecting the alongside the rails, this distance can be very greatly shortened.

When a train stands between a transformer and the relay, this relay will r'ece'ive current from the next transformer beyond, but, as can easily-be traced from the dla- I gram, this current is. in the wrong direction to cause a closing of the relay contacts, and W111 have a tendenc to open the contacts.

It will also be readi y seen that the middle points of the reinforced rail sections will be Two opposite zero signaling current. It is desirable to join these points in this manner :for the purpose of preventing1 as much as possible the unbalw ancing of t e propulsion current. These connections are indicated atm, m, m, in

Tt will be seen-thata train in any portion of any block will always cause the short-circuiting of one of the two rela s of this block,

and that since these two re ays have their contacts in series in the si al-controlling circuit, that circuit will be he d open and the signal guarding the entrance to that block Wlll remain at danger so long as the block is occupied. In leaving any block, a train before losing control of the last relay of that gains control of the first relay of the block succee ing block, and thereby holds the si nal behind the train at danger until suc time as:it is protected by-the signal at theentrance to the next block. The manner in; which the rela s are aflected by the presence of a train'wil be clearly seen from Fig. 2. By reason of the increased impedance of the end portions of the track rails at the block limits, as herein described, the distances at whichvadjacent relays of two adj ace'nt blocks will be short-circuited by the train can be very closely determined, so that there will be but a comparatively small overlapping of the blocks. p

It will further appear that by the arran ement described it is impossible for any refay to be operated except by current from the transformer which is intended to operate it. The arrangement of the circuits is made very simple,. but few line conductors being required, since the invention ermits the use of single-phase currents for t e signaling cir: cuits. 1

It will be obvious that many changes may be made in my invention; Thus, other means ma be employed'to increase the impedanceo the rails, the relays may be of. any

desired ty e, and various ot or changes may be made a within the scope, of my'inv ention. I claim I I 1. Ina continuous rail block signaling substantiall system, track rails having portions of increased impedance; substantially as de scribed.

2. In a continuous rail block signaling system, track rails having portions thereof near the ends of the blocks of increased impedance; substantially as described.

3. In' a continuous rail block signaling system, means for increasing the im edance of the track rails adjacent to the en s of the blocks, and signal controlling relays connected to the track rails at opposite sides of the portions thereof of increased impedance;

as described.

4. In a b ock signaling system, track rails which are electrically continuous for all currents, and having portions thereof provided with means for increasing their impedance,

' means for im ressing signaling currents u on the track rai s, and signal controlling re ays connected to the track rails adjacent to those portions thereof which are of increased impedance substantially as described.

5. In a block signaling system, track rails which are electrically continuous for all currents, means for increasing the impedance of said rails at the block limits, transformers connected to said rails at intermediate portions of the respective blocks, and signal controlling relays also connected to said rails between the portions of increased impedance and on o posite sides of the points of connection of't e transformers; substantially as de scribed.

6. In a block signaling system, track rails which are electrically continuous for all currents, and which are provided with ortions of increased impedance adjacent to tlie block limits, transformers connected to the track rails substantially midwa between the portions thereof of increase impedance, adjacent transformers being opposltely connected 'to said rails, signal controllin relays connected to the rails near the on s of the portions thereof of increased impedance, and sighaving nals controlled by the relays; substantially as described.

7. In a block signaling system, track rails which are electrically continuous for all currents, said rails having portions of increased impedance, two signal controlling relays connected across .the track rails between each two adjacent portions of increased impedance at points near the ends of such portions, said relays having signal controlling contacts in series with each other, and a transformer con-' nected to the track rails substantially midway between each two relays, adjacent transformers being oppositely connected to the track rails; substantially as described.

8. In a block signaling, system, track rails which are electrically continuous for all currents, said rails having portions of increased im edance, and conductors connecting said rai s at those portions thereof which are of increased impedance; substantially as described.

9. In a block si naling system, track rails ortions thereof at and adjacent to the'bloc limits reinforced to increase their impedance; substantially as described. 10. In a block signaling system, track rails having laminated reinforcements of magnetic metal secured to portions thereof at and adj acent to the block limits for the purpose of increasing their impedance; substantlally as described.

11. In a block signalin system, electrically continuous track raii s having portions thereof at and adjacent to the block limits reinforced by magnetic material between their heads and bases; substantially as described.

In testimony whereof, I have hereunto set my hand.

JOHN D. TAYLOR.

Witnesses:

H. M. Conwm, GEO. H. PARMELEE. 

